A related art laundry treating apparatus is provided with a cabinet which forms an exterior appearance thereof, a tub mounted in the cabinet, a drum rotatably mounted in the tub for washing laundry, and a motor fixedly secured to the drum passed through the tub for rotating the drum.
The tub is supported by springs and dampers in the cabinet, wherein the springs are provided to connect an upper side of an inside of the cabinet to an upper side of an outside of the tub, and the dampers are provided to connect a bottom of the inside of the cabinet to a lower side of the outside of the tub.
Particularly, the dampers are configured to be coupled to both sides of the lower side of the tub with hinges for attenuating vibration being transmitted to the tub when the drum rotates, respectively.
In more detail, each of the dampers is provided with a cylindrical cylinder connected to one of the both sides of the lower side of the tub with the hinge, a cylindrical piston connected to the bottom of the cabinet with the hinge to be movable within the cylinders, and a damping pad attached to an outside circumference of the piston for making friction with an inside circumference of the cylinder.
However, despite of the dampers mounted to the tub, the related art laundry treating apparatus has a limitation in attenuating the vibration.
That is, the related art laundry treating apparatus has a structure in which the motor is fixedly secured to a rear of the tub, with the rotation shaft of the motor connected to the drum passed through the rear of the tub, resulting in transmission of the vibration from the drum and the motor to the tub when the drum rotates. There have been problems in that, though attenuated, the vibration transmitted to the tub thus may be transmitted to the cabinet, and the vibration of the tub and the vibration of the cabinet caused by rotation of the drum thus may be increased more when the drum rotates in a dynamically unbalanced state.
In a dynamically balanced state, entire centrifugal force and entire moment of a rotation body caused by the centrifugal force become zero with respect to a rotation axis when a rotation body rotates. A rigid body may maintain the dynamic balance if a mass distribution is uniform with respect to a center of the rotation axis.
Accordingly, the dynamic balance of the laundry treating apparatus may be understood to be a case in which a mass distribution of the laundry with respect to the rotation axis of the drum is within an allowable range when the drum is rotating (A case when the drum rotates while vibrating within the allowable range).
Opposite to this, a dynamically unbalanced state of the laundry treating machine may be a state in which the mass distribution of the laundry with respect to the rotation axis of the drum is not constant when the drum rotates, which is a case when the distribution of the laundry in the drum is not uniform.